CN104545695B - A kind of two grades of dust and gas isolating constructions and comprise the dirt cup of this structure - Google Patents

Abstract

The invention discloses a two-stage dust-gas separation structure. The structure comprises a wind cover dust cylinder and a spiral dust-gas separation device. The first-stage separation of dust gas is realized through the cyclone cover, and the inside of the cyclone cover is provided with a secondary cyclone tube. And the spiral dust-air separation device located at the mouth of the cylinder, the dust gas after the first-stage separation is guided by the spiral dust-gas separation device, and forms an airflow rotating towards the bottom of the cylinder on the inner wall of the secondary cyclone cylinder. Driven by the centrifugal force, the dust spins down to the bottom of the cylinder and is collected in the secondary dust collection space. The air in the rotating air flow is drawn out by negative pressure to realize the second-stage dust-gas separation. The secondary dust and gas separation structure has a small number of components, which simplifies the assembly process and facilitates the improvement of the overall performance of the whole machine. At the same time, the structure is small in size, which can effectively reduce the dust cup space occupied by the secondary separation structure, achieve the largest ash storage volume, and improve the dust collection efficiency. It is suitable for use in various types of vacuum cleaners.

Description

A secondary dust-gas separation structure and a dust cup containing the structure

technical field

The invention belongs to the technical field of vacuum cleaner production, and in particular relates to a secondary dust-gas separation structure and a dust cup containing the structure.

Background technique

The vacuum cleaner is a cleaning appliance that uses the motor to drive the blades to rotate at high speed, and generates air negative pressure in the sealed housing, thereby sucking the dust into the dust collection device, and discharging the filtered air out of the fan at a very high speed. The vacuum cleaner is based on its function The classification includes dry vacuum cleaners and wet and dry vacuum cleaners. Dry vacuum cleaners generally include dust bag type and dust cup type.

Existing dust cup vacuum cleaners generally include a two-stage dust-air separation structure. The first-stage structure is used to filter large-scale dirt in the air, and the second-stage structure is used to separate and collect small dust particles and other sundries. The traditional two-stage structure The dust and gas separation structure generally forms a secondary cyclone through the cooperation of the dust cup filter cover plate and the cyclone body provided with several cyclone ports. This structure requires more parts, and the molds and assembly processes involved are relatively more. Complicated, the sealing of each link is difficult to control, and it is prone to air leakage and dust leakage, which affects the overall performance of the whole machine.

The previous two-stage dust-air separation dust cup structure is an axial layout, and the purpose of dust-gas separation is achieved through the axial superposition of layers of cones and cyclones, so that the ratio of the filter structure to the space of the dust cup is relatively small. Large, but too much occupies the volume of the dust collection dust cup, the dust storage space is limited, and this type of secondary dust-gas separation dust cup structure requires a relatively high and large dust cup volume, which is not suitable for small vacuum cleaners and Portable vacuum cleaners with limited range of use.

In view of the above problems, it is necessary to propose a new two-stage dust-gas separation structure to reduce the number of structural parts, simplify the assembly process, improve the overall performance of the whole machine, and effectively reduce the dust cup space occupied by the two-stage separation structure. Realize the largest ash storage volume, improve dust collection efficiency, and are suitable for use in various types of vacuum cleaners.

Contents of the invention

In view of this, the present invention provides a secondary dust-gas separation structure and a dust cup containing the structure, in order to reduce the number of parts of the structure, simplify the assembly process, improve the overall performance of the whole machine, and effectively reduce the secondary separation structure. The occupied dust cup space realizes the largest ash storage volume and improves the dust collection efficiency. It is suitable for the use of various types of vacuum cleaners.

According to the purpose of the present invention, a secondary dust-gas separation structure is proposed, including a windshield dust cylinder and a spiral dust-gas separation device, the windshield dust cylinder includes a cyclone cover for the first-stage dust-gas separation and is arranged on The secondary cyclone inside the cyclone hood, there is a gap between the secondary cyclone and the inner wall of the cyclone hood, the gap is used to form the air inlet duct after the first-level dust and gas separation,

The spiral dust and gas separation device is arranged at the mouth of the secondary cyclone, and the bottom of the secondary cyclone is also provided with an opening connected to the secondary dust collection space, and the air with dust is collected by the secondary cyclone. After the cyclone hood performs the first stage of dust and gas separation, at least a part of it is guided to the spiral dust and gas separation device through the air inlet duct, and under the guidance of the spiral dust and gas separation device, in the secondary cyclone The inner wall of the cylinder forms an airflow that rotates toward the bottom of the cylinder. The dust in the airflow is driven by centrifugal force to the bottom of the cylinder and is collected in the secondary dust collection space. The air in the rotating airflow is drawn out by negative pressure to achieve the second-level dust Gas separation.

Preferably, the spiral dust and gas separation device includes a spiral wind impeller for generating a secondary cyclone, the spiral wind impeller is provided with a number of blades inclined downwards, and the blades restrict the flow direction of the dust gas to swoop downwards .

Preferably, the spiral dust-gas separation device further includes an inner ring arranged on the inner ring of the spiral wind impeller, and a plurality of guiding guides are arranged on the side wall of the inner ring corresponding to the air outlet of the spiral wind impeller. Cutting surface, the guiding cutting surface constrains the dust flow to the outer ring of the spiral wind impeller and starts to form a rotating state.

Preferably, a windshield extends downwards from the inner circular wall of the spiral wind impeller.

Preferably, the windshield dust cylinder also includes an inverted dust shield arranged inside the secondary cyclone, a gap is provided between the dust shield and the secondary cyclone, and the gap is used to form a secondary cyclone. The first-level dust and gas separation air duct, the inner wall of the dust shield box is used to restrict the dust gas to rotate in the dust shield box to generate centrifugal force to resist the suction of negative pressure.

Preferably, the bottom of the secondary cyclone extends obliquely toward the lower center to form a tapered opening, so that dust can fall into the secondary dust collection space through the guidance of the tapered opening.

Preferably, a gap is provided between the bottom of the dust-shielding cylinder and the tapered opening, and is connected and fixed by several ribs, so that the dust ends in the state of rotating at the ribs, and the gap forms with the space between the ribs. The secondary ash inlet, the dust after secondary dust gas separation falls into the secondary dust collection space through the secondary ash inlet.

Preferably, the secondary dust collecting space is a secondary dust collecting cylinder arranged below the secondary cyclone, and the tapered opening extends to the secondary dust collecting cylinder and partially extends into the The inner side of the secondary dust collection tube forms the dust retaining flanging of the secondary dust collection tube.

A dust cup, comprising a main body of the cup body and a secondary dust-gas separation structure arranged inside the main body of the cup body, the space between the main body of the cup body and the secondary dust-gas separation structure forms a primary dust collection tube, the The side wall of the main body of the cup body is respectively provided with an air inlet and an air outlet, through which the dusty air is guided to the windshield dust cylinder of the secondary dust-gas separation structure, and the dusty air is carried out by the cyclone cover for the first time. After the primary dust and gas separation, at least a part of it passes through the cyclone hood and then enters the secondary cyclone for the second stage of dust and gas separation.

Preferably, the overall air inlet area of the spiral wind impeller is smaller than the air outlet area of the dust cup, so that the centrifugal force generated by the rotation is sufficient to resist the suction force of the negative pressure.

Preferably, a partition is arranged inside the main body of the cup body, and an opening extends downwards at the center of the partition, and a return air dust shield is provided on the opening above the spiral wind impeller. The windshield is connected and fixed to the edge of the opening through a number of cyclone ribs arranged around it, and the air after secondary dust and gas separation is drawn out by negative pressure through the gap between the cyclone ribs.

Preferably, the middle part of the return air dust baffle protrudes upwards to form an air guide cone to realize return air guidance.

Compared with the prior art, the advantages of the secondary dust-gas separation structure disclosed in the present invention and the dust cup containing the structure are:

The structure includes a windshield dust cylinder and a spiral dust-gas separation device. The first-stage separation of dust and gas is achieved through the cyclone hood. Under the guidance of the spiral dust-gas separation device, the dust gas after the first-stage separation forms an airflow rotating toward the bottom of the cylinder on the inner wall of the secondary cyclone cylinder, and the dust in the airflow is driven by centrifugal force to the bottom of the cylinder and is swept away. Collected in the secondary dust collection space, the air in the swirling airflow is drawn out by negative pressure to achieve the second stage of dust and gas separation. The secondary dust and gas separation structure only includes a cyclone cover, a secondary cyclone cylinder and a spiral dust and gas separation device, which effectively reduces the number of parts of the structure, simplifies the assembly process, and facilitates the improvement of the overall performance of the whole machine. At the same time, the structure is small in size, which can effectively reduce the dust cup space occupied by the secondary separation structure, achieve the largest ash storage volume, and improve the dust collection efficiency. It is suitable for use in various types of vacuum cleaners.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is a perspective view of a dust cup.

Figure 2 is a diagram of the internal structure of the dust cup.

Fig. 3 is a schematic structural diagram 1 of the windshield dust cylinder.

Fig. 4 is a structural schematic diagram 2 of the windshield dust cylinder.

Fig. 5 is a sectional view of the windshield dust cylinder.

Fig. 6 is a structural schematic diagram of a spiral dust-gas separation device.

Fig. 7 is a schematic diagram of the airflow direction of the spiral dust-gas separation device.

Figure 8 is a schematic diagram of the secondary dust and gas separation.

Figure 9 is a schematic diagram of the main body of the cup body.

Figure 10 is a sectional view of the dust cup.

Figure 11 is a diagram of the airflow direction of the dust cup.

Figure 12 is an exploded view of the dust cup.

The names of the corresponding parts represented by numbers or letters in the figure:

100, the main body of the cup body 200, the secondary dust and gas separation structure 300, the upper cover 400, the sealing ring 500, the base

110. Primary dust collector 120, air inlet 130, air outlet 140, partition 150, opening 160, return air dust baffle 170, cyclone rib 180, air guide cone 190, crimping 111, filter cotton

210. Windshield dust cylinder 220. Spiral dust and gas separation device

211, cyclone cover 212, secondary cyclone cylinder 213, air inlet duct 214, secondary dust collection cylinder 215, dust shielding cylinder 216, secondary dust and gas separation air duct 217, tapered opening 218, ribs 219, shielding Dust flanging 230, filter hole 231, secondary ash inlet 232, spiral groove

221, spiral air impeller 222, inner ring 223, outer ring 224, guiding section 225, windshield

detailed description

The traditional two-stage dust-gas separation structure requires many parts, and the molds and assembly processes involved are relatively many and complicated. The sealing of each link is difficult to control, and it is prone to air leakage and dust leakage, which affects the overall performance of the whole machine. performance. Moreover, the structure of the previous secondary dust-gas separation type dust cup is axially arranged, so that the ratio of the filter structure to the space of the dust cup is relatively large, and the dust collection volume of the dust cup is too much occupied, and the dust storage space is limited. , and this type of secondary dust-gas separation dust cup structure requires a relatively high and large dust cup volume, which is not suitable for small vacuum cleaners and portable vacuum cleaners, and the scope of use is limited.

Aiming at the deficiencies in the prior art, the present invention provides a two-stage dust-gas separation structure and a dust cup containing the structure, so as to reduce the number of parts of the structure, simplify the assembly process, improve the overall performance of the whole machine, and effectively reduce the secondary The dust cup space occupied by the stage separation structure realizes the largest ash storage volume and improves the dust collection efficiency. It is suitable for various types of vacuum cleaners.

The technical solutions of the present invention will be clearly and completely described below through specific embodiments. Apparently, the described embodiments are only some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Please refer to Fig. 3 to Fig. 8, a two-stage dust and gas separation structure, including a windshield dust cylinder 210 and a spiral dust and gas separation device 220, and the windshield dust cylinder 210 includes a cyclone for the first stage dust and gas separation The cover 211 and the secondary cyclone tube 212 arranged inside the cyclone cover 211, there is a gap between the secondary cyclone tube and the inner wall of the cyclone cover, and the gap is used to form the air inlet duct 213 after the primary dust and gas separation. The cyclone cover is provided with a filter hole 230. After the dusty air enters through the air inlet, the large debris is filtered through the filter hole 230 and collected in the first-stage dust collection tube 110. The air after the first-stage separation enters the air inlet duct 213 .

Wherein, the inner side of the upper end of the cyclone cover is provided with a spiral groove 232, so that the airflow rotates there to generate centrifugal force, which facilitates the airflow to spiral down into the spiral dust-gas separation device.

The spiral dust and gas separation device 220 is installed at the mouth of the secondary cyclone 212, and the bottom of the secondary cyclone 212 is also provided with an opening connected to the secondary dust collection space, wherein the secondary dust collection space is the secondary dust collection space. Barrel 214. After the air with dust is separated by the cyclone cover 211 for the first stage of dust and gas separation, at least a part of it is guided to the spiral dust and gas separation device 220 through the air inlet duct 213, and under the guidance of the spiral dust and gas separation device, The inner wall of the secondary cyclone 212 forms an airflow that rotates toward the bottom of the cylinder. The dust in the airflow is driven by centrifugal force to the bottom of the cylinder and is collected in the secondary dust collection cylinder 214. The air in the rotating airflow is drawn out by negative pressure. Realize the second level of dust and gas separation.

The spiral dust and gas separation device 220 includes a spiral wind impeller 221 for generating a secondary cyclone. The spiral wind impeller 221 is provided with a number of downward-sloping blades, which can restrict the flow direction of dust and gas to swoop downward to form a spiral air flow.

The spiral dust and gas separation device 220 also includes an inner ring 222 arranged on the inner ring of the spiral wind impeller 221, and the inner ring 22 is provided with a plurality of guide cut surfaces 224 on the side wall corresponding to the air outlet of the spiral wind impeller 221, and the guide cut surfaces constrain The dust flows to the outer ring of the spiral wind impeller and begins to form a rotating state. Wherein, an outer ring is arranged on the outer ring circumference of the spiral wind impeller, and through the functions of the inner and outer rings, the airflow guidance is realized, and the structural strength and stability of the spiral wind impeller are improved. A windshield 225 extends downwards from the inner circular wall of the spiral wind impeller.

The windshield dust cylinder 210 also includes an inverted dust shielding cylinder 215 arranged inside the secondary cyclone 212. There is a gap between the dust shielding cylinder and the secondary cyclone, and the gap is used to form a secondary dust and gas separation air duct 216. The dust-laden air realizes spiral rotation in the secondary dust-air separation air duct to generate centrifugal force to make the dust fall along the inner wall of the secondary cyclone. The inner wall of the dust-shielding cylinder is used to restrain the dust gas rotating in the dust-shielding cylinder to generate centrifugal force to resist the suction force of the negative pressure, so as to realize the effective separation of the dust-gas.

The bottom of the secondary cyclone extends obliquely to the lower center to form a tapered opening 217, allowing dust to fall into the secondary dust collecting cylinder through the guidance of the tapered opening.

There is a gap between the bottom of the dust-proof tube 215 and the tapered opening 217, and it is connected and fixed by several ribs 218, so that the dust ends in the state of rotation at the rib, which is convenient for the whereabouts of the dust. A secondary ash inlet 231 is formed, and the dust after secondary dust gas separation falls into the secondary dust collection space through the secondary ash inlet. The number of ribs can be 1, 2, 3 or more evenly arranged along the periphery of the dust-shielding cylinder, and the specific number is not limited.

The tapered opening 217 extends to the secondary dust collection cylinder 214, and partly extends into the inner side of the secondary dust collection cylinder to form a dust retaining flange 219 of the secondary dust collection cylinder to prevent dust from flowing back. The protruding position of the dust-blocking flanging can generally be designed to fall into the inside of the projection where the dust-shielding cylinder is located, so as to ensure the effectiveness of dust-blocking, and the specific protruding position is not limited.

Among them, the windshield dust cylinder and the spiral dust-gas separation device can be integrally processed and formed. After forming, the spiral dust-gas separation device is directly installed at the center of the windshield dust cylinder to complete the assembly. The specific forming method is not limited.

In addition, the secondary dust-gas separation structure can also be directly processed and formed in one piece, and the specific forming and assembling methods are not limited.

Please refer to Fig. 1, 2 and Fig. 9 to Fig. 12 together. A dust cup includes a cup body body 100 and a secondary dust-gas separation structure 200 arranged inside the cup body body 100. The cup body body and the secondary dust The space between the gas separation structures forms a first-stage dust collection tube 110, which realizes the collection of large sundries. The side wall of the main body of the cup body is respectively provided with an air inlet 120 and an air outlet 130, through which the dusty air is guided to the dust cylinder of the secondary dust-air separation structure, and the dusty air is carried out by the cyclone cover 211 for the first time. After the primary dust and gas separation, at least part of it passes through the cyclone hood and then enters the secondary cyclone 212 for the second stage of dust and gas separation.

Among them, the overall air inlet area of the spiral wind impeller is smaller than the air outlet area of the dust cup, so that it can have a higher rotation speed to resist the suction of negative pressure under the same air volume.

The inner side of the main body of the cup body is provided with a partition 140, and the center of the partition extends downwards with an opening 150. The opening is located above the spiral wind impeller and is provided with a return air dust baffle 160. The return air dust baffle passes through some The cyclone ribs 170 are connected and fixed to the edge of the opening, and the air after secondary dust-air separation is drawn out by negative pressure through the gaps between the cyclone ribs. The upper end of the cyclone hood is covered by setting a partition, so that the dust gas filtered by the cyclone hood will be guided into the spiral dust-gas separation device from the upper end of the air inlet duct to realize the air inlet guidance. Among them, the middle part of the partition is a downward-sloping arc structure, which is convenient for the movement and guidance of dust and gas.

The middle part of the return air dust shield 160 protrudes upwards to form an air guide cone 180 to realize return air guidance. Through the cooperative action of the cyclone rib and the air guide cone, the dust gas after the secondary separation is still kept in a high-speed rotation state after passing through the return air dust baffle.

Among them, the bottom of the return air dust shield is also provided with a curling edge, which is convenient for quick assembly with the dust shield and achieves effective centering.

The invention discloses a two-stage dust and gas separation structure and a dust cup containing the structure. The structure includes a wind cover dust cylinder and a spiral dust and gas separation device. The first stage separation of dust and gas is realized through the cyclone cover. The inside of the hood is equipped with a secondary cyclone and a spiral dust-gas separation device at the mouth of the cylinder. The dust gas after the first-stage separation is guided by the spiral dust-gas separation device, and is formed on the inner wall of the secondary cyclone to the bottom of the cylinder. The rotating airflow, the dust in the airflow is driven by the centrifugal force to the bottom of the cylinder and is collected in the secondary dust collection space. The air in the rotating airflow is drawn out by negative pressure to achieve the second stage of dust and gas separation. The secondary dust and gas separation structure only includes a cyclone cover, a secondary cyclone cylinder and a spiral dust and gas separation device, which effectively reduces the number of parts of the structure, simplifies the assembly process, and facilitates the improvement of the overall performance of the whole machine. At the same time, the structure is small in size, which can effectively reduce the dust cup space occupied by the secondary separation structure, achieve the largest ash storage volume, and improve the dust collection efficiency. It is suitable for use in various types of vacuum cleaners.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (11)

1. two grades of dust and gas isolating constructions, it is characterised in that: include that fan housing dirt cup and spiral dust and gas are divided From device, described fan housing dirt cup includes the whirlwind cover separated for first order dust and gas and is arranged at described whirlwind Two grades of cyclone cylinders within Zhao, are provided with space between described two grades of cyclone cylinders and the inwall of described whirlwind cover, This space wind inlet channel after forming the separation of one-level dust and gas,

Described spiral dust and gas segregation apparatus is arranged at the nozzle of described two grades of cyclone cylinders, described two grades of whirlwind It is additionally provided with, at the bottom of the cylinder of cylinder, the perforate being connected to two grades of dust collecting space, with the air of dust by described whirlwind cover After carrying out first order dust and gas separation, at least some of the most described spirally by the guiding of described wind inlet channel Dust and gas segregation apparatus, described spiral dust and gas segregation apparatus includes the spiral fan blade for producing two grades of whirlwind Wheel, described spiral wind impeller is provided with some downward-sloping blades, the flowing of described blade constraint dust and gas Dive diagonally downward in direction；With the air of dust under the guiding of this spiral dust and gas segregation apparatus, Described two grades of cyclone cylinder inwalls are formed to the air-flow rotated at the bottom of cylinder, and the dust in this air-flow drives at centrifugal force At the bottom of being threaded under Xia tin and be collected in two grades of dust collecting space, the air in swirling eddy is extracted out by negative pressure, Realize second level dust and gas to separate.

Two grades of dust and gas isolating constructions the most as claimed in claim 1, it is characterised in that: described spiral dirt Air separation also includes the interior annulus being arranged at described spiral wind impeller inner ring, and described interior annulus is with described Being provided with some guiding tangent planes on the sidewall that the air outlet of spiral wind impeller is corresponding, described guiding tangent plane retrains Dust and gas flows to the outer shroud of spiral wind impeller and initially forms rotation status.

Two grades of dust and gas isolating constructions the most as claimed in claim 2, it is characterised in that: described spiral fan blade The inner circle ring wall of wheel has downwardly extended deep bead.

Two grades of dust and gas isolating constructions the most as claimed in claim 1, it is characterised in that: described fan housing dirt cup Also include being arranged at the internal inverted dust-break cylinder of described two grades of cyclone cylinders, described dust-break cylinder and described two grades of rotations Being provided with space between air duct, this space separates air channel, the inner side of described dust-break cylinder for forming two grades of dust and gas Wall changes the line of production raw centrifugal force to resist the suction of negative pressure in order to retrain dust and gas in this dust-break cylinder inward turning.

Two grades of dust and gas isolating constructions the most as claimed in claim 4, it is characterised in that: described two grades of whirlwind The center downwards, bottom of cylinder tilts to extend formation taper perforate, makes dust leading by this taper perforate In falling into two grades of dust collecting space.

Two grades of dust and gas isolating constructions the most as claimed in claim 5, it is characterised in that: described dust-break cylinder It is provided with gap between bottom and described taper perforate, and is connected by some muscle fixing, make dust at bar muscle Place terminates the state rotated, and the space between this gap and bar muscle forms two grades of ash inlets, and two grades of dust and gas separate After dust in two grades of ash inlets fall into two grades of dust collecting space.

Two grades of dust and gas isolating constructions the most as claimed in claim 5, it is characterised in that: described two grades of dusts Space is to be arranged at two grades of dust-collecting cylinders below described two grades of cyclone cylinders, and described taper perforate extends to described On two grades of dust-collecting cylinders, and part stretches into the dust-break flange forming two grades of dust-collecting cylinders inside described two grades of dust-collecting cylinders.

8. a dirt cup, it is characterised in that: include glass body main body and be arranged at this glass of body body interior as Two grades of dust and gas isolating constructions described in any one of claim 1-7, described cup body main body and described two grades of dust and gas Space between isolating construction forms single stage of dust collection cylinder, and the sidewall of described cup body main body is respectively equipped with air inlet With air outlet, dust laden air guides the fan housing dirt cup to described two grades of dust and gas isolating constructions by this air inlet On, after this dust laden air is carried out first order dust and gas separation by whirlwind cover, at least partially by this whirlwind cover The described two grades of cyclone cylinders of rear entrance carry out second level dust and gas separation.

9. dirt cup as claimed in claim 8, it is characterised in that: the overall air intake of described spiral wind impeller Area is less than dirt cup air-out area so that rotates the centrifugal force produced and be enough to resist the suction of negative pressure.

10. dirt cup as claimed in claim 8, it is characterised in that: it is provided with inside described cup body main body Dividing plate, described dividing plate center has downwardly extended perforate, described perforate is positioned on described spiral wind impeller Position, side is provided with return air dust board, some whirlwind muscle that this return air dust board is arranged by periphery and perforate Edge connects fixing, and the gap through between whirlwind muscle of the air after two grades of dust and gas separate is extracted out by negative pressure.

11. dirt cup as claimed in claim 10, it is characterised in that: in the middle part of described return air dust board upwards Convex to form gas deflector cone, it is achieved return air guides.